Saturnian ocean Saturn's largest moon Titan may have a huge subsurface ocean according to new data from NASA's Cassini spacecraft.

While scientists have learnt a great deal about Titan atmosphere and surface, very little is known about the Saturnian moon's interior.

The new study, published in the online version of the journal Science, supports the idea of a global ammonia-doped liquid water ocean less than a hundred kilometres below Titan's methane soaked surface.

The teamclosely examined Titan's rotation and orbit to draw conclusions about its interior.

Cassini, which has been exploring the ringed world of Saturn since 2004, has flown past Titan more than 80 times, including six close flybys.

Scientists used subtle changes in radar signals from Cassini during these flybys to develop a gravity map, or geoid, of the moon.

They found that as Titan travels along its 16-day elliptical orbit around Saturn, the geoid changes.